<form method="post">
    {% csrf_token %}
    <input type="hidden" name="card_id" value="{{ card.id }}"/>
    <input type="hidden" name="solved" value="{{ solved }}"/>
    {% if solved %}
        <input type="submit" value="✅ I know"/>
    {% else %}
        <input type="submit" value="❌ I don't know"/>
    {% endif %}
</form>
